Sarcoidosis-like reaction associated with tocilizumab in a patient with giant cell arteritis: a case based review.

We report a 71-year-old man with confirmed giant cell arteritis (GCA) who underwent temporal artery biopsy. Following 2.5 years of combination therapy with tocilizumab (TCZ) (162 mg/w) and glucocorticoids (tapered over 2.5 years to prednisolone 1 mg/day), erythematous facial papules and red eye developed. Skin biopsy revealed multiple non-caseating epithelioid granulomas containing multinucleated giant cells, without evidence of infection. Serum angiotensin-converting enzyme levels and soluble interleukin-2 receptor levels were within normal limits, and imaging showed no systemic sarcoidosis involvement. TCZ-induced sarcoidosis-like reaction was suspected. TCZ was discontinued 3 months after the onset of the lesions. Considering the risk of GCA recurrence, PSL was increased to 2 mg/day. The erythematous facial papules and red eye showed improvement 5 months after the onset of the lesions. There was no GCA recurrence. Biologic agents including TCZ are cornerstones in autoimmune disease management but may paradoxically induce immune-mediated reactions, including sarcoidosis-like reactions due to immune dysregulation. A literature search identified 6 previously published cases of TCZ-associated sarcoidosis-like reactions. Among these, ocular involvement in the form of scleritis was observed only in the present case. We should remain vigilant for sarcoidosis-like reaction during TCZ therapy and consider individualized monitoring and treatment adjustment.